wats the best way to connect them to a PC?

through some sort of usb interface I'd imagine

A recording interface such as:
Creative E-MU
Digidesign MBOX
Presonus Firebox/Audiobox etc
M-Audio Fast Track

Everyone has their own needs/preference, there are a lot of options, and they start around $99

edit: posted a topic about recording interfaces! http://metal-archives.com/board/viewtopic.php?p=1291497

One tip, make sure you go to the shop and talk to the guys, a lot of the interfaces are shit and it's not until you talk to someone who's in the know till you know

It is very unlikely that anyone in a shop will know a good recording interface from their asshole.

On a budget? The Line 6 interfaces are probably the best deal for a cheaper interface, as they also include the Pod farm.

Got a bit more cash? M-Audio Profire 610 is a good deal. The M-Audio Profire 2626 is unbeatable in the under $1000 price range.

Got about $1K to spend? RME Fireface. The 400 and 800 both go for around $1000 used, for some reason, despite costing $500 apart.

"someone who's in the know" is generally not a music store employee. Guitar Center has been pushing the Line 6 amps with awful preset tones and a line out for a while, the tones were designed to sound like high end Mesa and Marshall amps, and it is designed with POD technology so you get a professional tone when you plug it into your computer.

Figure out what features/specs you need. Look at sites that review music gear, look at user reviews on sites that sell them, ask on music forums, and make an educated decision. Music store employees, especially chain stores, are the last people you should ask.

Not to mention the absolute saturation of Marshall's MG series. When I was 16 I went to the local music store and asked for the best amp I could get for $1000 dollars. They sold me a Marshall MG250DFX. I was new to guitars, so I thought I was getting a good amp.

I'd talk to someone who doesn't have the preoccupation of making money off you.

Yeah because I'd go to a bass shop to buy a drum kit.

I went to a "Digital Shop".
Which sells monitors, mixers, recording equipment, condenser mic's, keyboards, software etc.

I'm just saying, better to buy one that you know someone else has had a good experience with or knows about.

The guy sold me one that was cheaper but better for what I needed it for, a lot easier to use and it's been perfect.

I guess people in shops in New Zealand aren't cunts like everywhere else then.

Maybe they don't work on commission. A lot of music stores carry a full range of audio gear, and in general, you can learn more by doing research yourself than by talking to someone who is trying to sell you a product.

As far as I know there are also cables, that can connect XLR to USB. Does anyone know if there's a loss of sound quality compared to a piece of hardware like the ones mentioned above?

Yes.